<!DOCTYPE html>
<html lang="zh">
<head>
    <meta charset="UTF-8">
    <style>
        #button {
            width: 112px;
            height: 40px;
            background-color: #4e6ef2;
            font-size: 17px;
            color: white;
            border-radius: 10px;
            box-shadow: none;
            border: 0;
            font-family: Arial,sans-serif;
        }
    </style>
</head>
<body>
    <input id="number1" type="text">
    +
    <input id="number2" type="text">
    =
    <input id="answer" type="text">
    <button id="button" onclick="">百度一下</button>
    <div id="d"></div>
    <script type="application/javascript">
        let answer = document.getElementById("answer");
        let number1 = document.getElementById("number1");
        let number2 = document.getElementById("number2");
        let button = document.getElementById("button");
        window.onload = function () {
            button.addEventListener('click', function () {
                answer.value = parseInt(number1.value) + parseInt(number2.value);
                let elementById = document.getElementById("d");
                elementById.innerHTML += '<button>SB</button>';
            });
        };

    </script>
</body>
</html>